The U.S. Navy has now developed threetypes of unmanned surface vessels (USVs)

— and deployed at least two of them —
and this year will take possession of two
more types of USVs as it develops the associated technology, including autonomy,
and expands the potential missions they
may perform for the fleet. Mine countermeasures (MCM) is the initial mission of
four of them, but the Navy is looking at
other payloads that could expand their mission portfolio and keep more Sailors out of
harm’s way.

In fall 2014, the Navy deployed the Mine-Hunting
Unit USV, an 11-meter rigid-hull inflatable boat
equipped with an AQS-24A mine-hunting sonar, to the
U.S. Fifth Fleet in the Persian Gulf. The Mine-Hunting
Unit was a rapid-acquisition project supported by the
Navy and Northrop Grumman. The AQS-24A is being
replaced by the more capable AQS-24B and the boats
have been kept deployed in the region to stand ready to
counter mines.

“We actually have three [Mine-Hunting Units] outthere today,” said Howard Berkof, the Navy’s deputyprogram manager of unmanned maritime systems.“They are being used in exercises and they are capableof responding to any needs that happen to arise. Thefourth system is going through testing stateside andwill be shipped out to the operational environment atAnother USV that has entered operational servicerecently is the Wave Glider, also known as the SHARC(Sensor Hosting Autonomous Remote Craft). It isoperational with the U.S. Navy in an anti-submarinewarfare (ASW) surveillance role, a Liquid Roboticsofficial said.

The SHARC consists of a surface float that houses
the solar cells, mission electronics and communications equipment. Tethered below the float is a sub that
propels the vehicle using wave energy.

Typically deployed from a ship, the SHARC can tow
underwater sensors and sensor arrays and carry other
payloads. The vehicle can travel at up to 3 knots, with
the average speed being 1. 8 to 2 knots. The distance
traveled depends on the wave energy and sea states. A
SHARC can operate at sea up to a year, depending on
the degree of bio-fouling — or accumulation of microorganisms, plants, algae or animals — experienced on
the system. Its system uplinks data via satellite.

Gary Gysin, president and chief executive of Liquid
Robotics, a Boeing company, said the company’s Wave
Glider is operational in two modes of ASW surveillance.
One mode is as a node in a “picket fence” ASW barrier.
A number of Wave Gliders spaced apart in an array collect acoustic data on undersea targets passing through
the barrier from bottom sensors and transmit the data
to a shore station via uplink to a satellite. The barrier
can be repositioned remotely.

The second mode is as a mobile sensor, with theWave Glider using a towed hydrophone, able to movefrom spot to spot in and out of areas of interest tosearch for or investigate contacts of interest. Gysindescribed it as a “mobile sonobuoy.”Gysin was not at liberty to reveal the locations ofthe Wave Gliders nor the number purchased by theNavy. He did say that Liquid Robotics has built morethan 400 units for various customers. The cost of abasic Wave Glider without customer-determined mis-sion systems is approximately $300,000.

Yet to deploy is the Remote Multi-Mission Vehicle
(RMMV), a diesel-powered semi-submersible USV
developed for the Remote Mine-hunting System built
by Lockheed Martin. It was designed to deploy the